We have a Joomla 1.5.9 website with JForms component and MariaDB of unknown version, but definitely corresponding to MySQL 5.x. I have administered it through GUI (both backend and frontend) for two years, but now I see the code for the first time. I have some experience with php programming and I am quite proficient with SQL, but this is my first Joomla experience.
The JForms version is optimized for MySQL 4, which leads to an error while saving a form (or better: while creating a database table for the form). I know exactly what I need to change in the SQL code, but I didn't find where are the queries produced, and where to change the CREATE TABLE syntax to match the database version.
The clean solution would be to upgrade the component completely. We will do it someday, but none of us has time to do so yet, and even though it's a mess, it handles everyday tasks quite well. We need inserting in the existing forms almost every day, but we didn't need to create a new form for years and we probably won't need it before complete upgrade of the site, so this is not worth risking other bugs due to "upgrade" to a version incompatible with other parts of our website.
EDIT:
JForms version information retrieved from the site: JForms 0.7 RC2 (402) [ 08-August-2010 14:07 GMT ]